The present invention refers to a vibration damping device for microscopes especially the invention relates to a vibration damping device for confocal scanning microscopes and confocal laser scanning microscopes.
It is vital for all the microscopic application that the distance between the objective and the object is constant during image capture. Vibration may cause a non-constant distance during image capture which may result in a reduced image quality. Vibration is a great inhibitor of microscope performance and it becomes a greater problem as the expected magnification and desired image quality increase, being particularly sensitive in the field of confocal laser scanning microscopy. At the threshold of the problem are vibrations which derive from the environment, such as footsteps, power applications, vehicles and other movements in the vicinity. It is assumed that suitable isolation means has been provided to reduce the effect of such vibrations on the microscope base or the table a microscope rests on. There remain, nonetheless, inherent vibrations, i.e., those deriving from devices built in the microscope itself, for example, electric motors, fans and other dynamics of microscope accessories.
The prior art provides several solution for the reduction of vibrations in microscope stands or in special elements of the whole microscope. U.S. Pat. 4,168,881 by Harold E. Rosenberger et. al., granted Sep. 25, 1979, discloses a construction of a microscope stand which reduces vibration effects. Here the objective mount is isolated from the superstructure. The microscope stage is mounted upon the pillar by means chosen to lend the stage a large measure of the pillar""s rigidity. The stage has a relatively wide, vertical span of mounting bearings in contact with the pillar and the interface is relatively low on the pillar. The objective lens is also mounted in rigid relation to the pillar, by a strong cantilever arm rising at a low angle from the pillar and stoutly and rigidly held on the pillar. The eyepiece lens, or other viewing apparatus, is mounted on an arm, also cantilevered from the pillar, which extends over and around the objective mounting arm but which does not touch it anywhere. When the microscopist, or a bystander, touches the eyepiece mounting arm or the superstructure, vibrations and deflections which he might thereby introduce are to a large extent absorbed by the eyepiece mounting arm before they can be transmitted to the pillar or through it to the objective or stage mounts An introduced complexity in structure enables the reduction of vibrations.
U.S. Pat. No. 5,764,409 by James B. Colvin, entitled: ELIMINATION OF VIBRATION BY VIBRATION COUPLING IN MICROSCOPY APPLICATIONS, granted Jun. 09, 1998 shows a base for the microscope being placed over an opening in the wafer sorter. A translational apparatus is attached to the base for lowering a charge coupled device camera into an opening in the wafer sorter. A compact housing containing microscope optics is coupled to the camera. A vibration reducing apparatus is coupled to the microscope optics for preventing movement of the camera relative to the chip.
U.S. Pat. No. 5,731,896 by Hans Baumann et. al. entitled: MICROSCOPE, granted Mar. 24, 1998 shows a microscope which has the optically imaging portion of its optical arrangement separated from the object to be observed. The microscope has at least one force exerting drive element for the compensation of vibrations acting on the optical arrangement from its surroundings in at least one direction perpendicular to the optical axis. The drive element is installed in or on the microscope. The elimination of vibrations requires complicated control electronics and increases the cost of a microscope.
An additional vibration preventing device for a microscope is disclosed in the JP-Patent Application JP10148235. The disclosed device generates a noise which supplies an acoustic wave of reverse phase to this noise, which is for example generated in the sample chamber. The two kinds of sounds are negated each other. Vibration is remarkably reduced. Again, the system requires a complicated set-up to achieve the elimination of the vibrations.
It is therefore the object of the present invention to provide means which effectively reduce the inherent vibrations of a microscope.
The aforesaid object is achieved by vibration damping device for a microscope comprising a piece of foam rubber and a weight attached to said piece of foam rubber.
It is an other object of the invention to provide a microscope which allows, despite the inherent vibrations of the microscope, the capturing of high quality images
This object is achieved by a microscope comprising a stand, at least one focusing device movably mounted to the stand, and a vibration damping device attached to at least one focusing device.
What has been recognized according to the present invention is firstly that by mechanically coupling the vibration damping device to a movable part of a microscope, the inherent vibrations and vibrations induced by external sources are reduced efficiently. The external sources for example are: air condition, fans used for external electronic devices, airplanes, vibrations of the building etc. The inherent vibrations arouse from electromotors and/or mechanical gears mounted in the stand of the microscope. The stage and/or the objective is moved by the electromotors along the optical axis in order to focus on one sample plane. Once the focus on the selected sample plane is achieved it is vital for the capturing of high quality images that the focus stays at this plane during the whole image capturing process. The vibration damping device is coupled to the stage and/or the objective to minimize the effect of the inherent vibrations on the constant focus during image capture.
It has proven advantageous that the housing of the vibration damping device is attached directly to the part of the microscope of which the vibrations should be reduced. To achieve a efficient vibration damping the vibration damping device need to be mechanically coupled to the part of the microscope which requires the damping. It is advantageous as well to attach the foam rubber with the mounted weight to the part of the microscope which requires damping. Consequently, the housing is not necessary to achieve the damping effect. It provides a better appearance of the whole vibration damping device and does not allow any manipulations of the vibration damping device.
The present invention is advantageous since with the vibration damping device a significant reduction of the vibrations is achieved. This enables that the image capture is done in one single plane of the object and is not disturbed by vibrations caused for example by the electromotor for moving the stage or the electromotor for moving the objective. The movement for the stage and the objective is along the optical axis.